copy-initialization. We previously got this wrong in a couple of ways:
- we only looked for copy / move constructors and constructor templates for
this copy, and thus would fail to copy in cases where doing so should use
some other constructor (but see core issue 670),
- we mishandled the special case for disabling user-defined conversions that
blocks infinite recursion through repeated application of a copy constructor
(applying it in slightly too many cases) -- though as far as I can tell,
this does not ever actually affect the result of overload resolution, and
- we misapplied the special-case rules for constructors taking a parameter
whose type is a (reference to) the same class type by incorrectly assuming
that only happens for copy/move constructors (it also happens for
constructors instantiated from templates and those inherited from base
classes).
These changes should only affect strange corner cases (for instance, where the
copy constructor exists but has a non-const-qualified parameter type), so for
the most part it only causes us to produce more 'candidate' notes, but see the
test changes for other cases whose behavior is affected.
llvm-svn: 280776
Because references must be initialized using some evaluated expression, they
must point to something, and a callee can assume the reference parameter is
dereferenceable. Taking advantage of a new attribute just added to LLVM, mark
them as such.
Because dereferenceability in addrspace(0) implies nonnull in the backend, we
don't need both attributes. However, we need to know the size of the object to
use the dereferenceable attribute, so for incomplete types we still emit only
nonnull.
llvm-svn: 213386
This allows clang to use the backend parameter attribute 'returned' when generating 'this'-returning constructors and destructors in ARM and MSVC C++ ABIs.
llvm-svn: 185291
The backend will now use the generic 'returned' attribute to form tail calls where possible, as well as avoid save-restores of 'this' in some cases (specifically the cases that matter for the ARM C++ ABI).
This patch also reverts a prior front-end only partial implementation of these optimizations, since it's no longer required.
llvm-svn: 184205
Richard Smith